How much Knock is normal?
08-22-2014, 05:52 PM
#1
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Location: Portland,Or
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How much Knock is normal?
Scanned my car with Scan9495, I have a little knock retard and was wondering what is normal? I also had DTC18, checked the fuses and they were fine. Apparently one of my injector clips was loose. Fixed that and now need to address the knocking issue.
08-22-2014, 08:42 PM
#3
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Re: How much Knock is normal?
It depends when you get the knock. A little knock is normal on whacking the throttle and on upshifts, but you certainly don't want any when you are just cruising around normally. It also might be related to your fuel quality and octane, so keep that in mind. Other things to look for is banging exhaust and worn motor mounts. And if your sensor was never changed, it could be deteriorating as well.
08-23-2014, 12:09 PM
#6
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Re: How much Knock is normal?
Here is the Scan9495 link http://www.mediafire.com/view/6o5pj4...P9RR407899.csv
It mostly seems to happen when idling, I need to get under there and check the exhaust.
It mostly seems to happen when idling, I need to get under there and check the exhaust.
08-23-2014, 04:01 PM
#7
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Re: How much Knock is normal?
You do have "a little" (less than 1-degree) at idle when the vehicle is stationary, and it bumps up to 2 to 3 degrees with the engine at idle RPM, but the vehicle moving.... but you have up to 9-degrees when you nail the throttle. That's not "a little".
In all cases, the knock retard it driven by knock count increases.
At idle seems like you have a lot of spark advance - up to 30-degrees, while I'm used to seeing closer to 20-degrees. The tuner may have done that to compensate for the cam.
Your left side fuel trims are severely elevated in Cells 10 (154) and 11 (147). Something is screwed up with the fuel on the left side. In both cases of high knock at WOT, as the RPM increases, the left O2 sensor reading starts to drop, indicating it's leaning out. I wonder if you have an injector going static at high duty cycle. What size are the injectors?
At idle, the LTFT's are both at about the same level (133/131) and not significantly elevated. Almost like it's running low on fuel on the left side at high RPM. But, the knock is starting even before you reach the point where the left side is going lean. You get it as soon as you hit the throttle.
In all cases, the knock retard it driven by knock count increases.
At idle seems like you have a lot of spark advance - up to 30-degrees, while I'm used to seeing closer to 20-degrees. The tuner may have done that to compensate for the cam.
Your left side fuel trims are severely elevated in Cells 10 (154) and 11 (147). Something is screwed up with the fuel on the left side. In both cases of high knock at WOT, as the RPM increases, the left O2 sensor reading starts to drop, indicating it's leaning out. I wonder if you have an injector going static at high duty cycle. What size are the injectors?
At idle, the LTFT's are both at about the same level (133/131) and not significantly elevated. Almost like it's running low on fuel on the left side at high RPM. But, the knock is starting even before you reach the point where the left side is going lean. You get it as soon as you hit the throttle.
Last edited by Injuneer; 08-23-2014 at 04:06 PM.
08-23-2014, 04:50 PM
#8
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Re: How much Knock is normal?
You do have "a little" (less than 1-degree) at idle when the vehicle is stationary, and it bumps up to 2 to 3 degrees with the engine at idle RPM, but the vehicle moving.... but you have up to 9-degrees when you nail the throttle. That's not "a little".
In all cases, the knock retard it driven by knock count increases.
At idle seems like you have a lot of spark advance - up to 30-degrees, while I'm used to seeing closer to 20-degrees. The tuner may have done that to compensate for the cam.
Your left side fuel trims are severely elevated in Cells 10 (154) and 11 (147). Something is screwed up with the fuel on the left side. In both cases of high knock at WOT, as the RPM increases, the left O2 sensor reading starts to drop, indicating it's leaning out. I wonder if you have an injector going static at high duty cycle. What size are the injectors?
At idle, the LTFT's are both at about the same level (133/131) and not significantly elevated. Almost like it's running low on fuel on the left side at high RPM. But, the knock is starting even before you reach the point where the left side is going lean. You get it as soon as you hit the throttle.
In all cases, the knock retard it driven by knock count increases.
At idle seems like you have a lot of spark advance - up to 30-degrees, while I'm used to seeing closer to 20-degrees. The tuner may have done that to compensate for the cam.
Your left side fuel trims are severely elevated in Cells 10 (154) and 11 (147). Something is screwed up with the fuel on the left side. In both cases of high knock at WOT, as the RPM increases, the left O2 sensor reading starts to drop, indicating it's leaning out. I wonder if you have an injector going static at high duty cycle. What size are the injectors?
At idle, the LTFT's are both at about the same level (133/131) and not significantly elevated. Almost like it's running low on fuel on the left side at high RPM. But, the knock is starting even before you reach the point where the left side is going lean. You get it as soon as you hit the throttle.
08-24-2014, 10:22 AM
#9
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Re: How much Knock is normal?
Sort of odd you had the DTC's at the beginning of the log, then they cleared. Did you clear them? If it was missing one injector, it would elevate the LTFT's. But when the injector started working, it would end up running rich.
Clear the PCM (pull "PCM BAT" fuse for 30 seconds), then verify you have 128 in all cells. Then drive it normally for a few days. I would stay off full throttle bursts, to avoid any potential damage from a lean condition. After a few days, look at the LTFT's to see if they have gone back to where they were in the data log that you posted. That will tell you if the LTFT's were a derivative of one injector not working.
Clear the PCM (pull "PCM BAT" fuse for 30 seconds), then verify you have 128 in all cells. Then drive it normally for a few days. I would stay off full throttle bursts, to avoid any potential damage from a lean condition. After a few days, look at the LTFT's to see if they have gone back to where they were in the data log that you posted. That will tell you if the LTFT's were a derivative of one injector not working.
09-01-2014, 12:51 PM
#11
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Re: How much Knock is normal?
Injuneer, could you take a look at my latest log? I only get to drive the car on the weekends. Ive pulled the pcm bat fuse and probably put about 50-60 miles on it. It looks like it's still getting knock retard. Ive checked for vacuum leaks and exhaust leaks. http://www.mediafire.com/view/3raku3...P9RR407899.csv
09-02-2014, 01:28 PM
#12
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Re: How much Knock is normal?
Yes, still getting up to 9-deg of knock retard. Plus the fraction of a degree for most of the log.
Did you check for the exhaust system contacting the body? Also look at the motor mounts... particularly the passenger side, since it's sitting right next to the knock sensor.
You are getting the 9-deg of retard with 25% throttle. It's not going into PE mode, so I can't look at the O2 sensor readings in PE mode. When you get in the upper cells, the left side is adding 9.4% extra fuel, while the right side is only adding a percent or two. At idle, its different - left side is +/- 0 and the right side is adding 4.7%.
You have to rule out the mechanical noises.
Have you asked the tuner to comment on knock retard vs. spark advance vs. RPM/MAP?
Did you check for the exhaust system contacting the body? Also look at the motor mounts... particularly the passenger side, since it's sitting right next to the knock sensor.
You are getting the 9-deg of retard with 25% throttle. It's not going into PE mode, so I can't look at the O2 sensor readings in PE mode. When you get in the upper cells, the left side is adding 9.4% extra fuel, while the right side is only adding a percent or two. At idle, its different - left side is +/- 0 and the right side is adding 4.7%.
You have to rule out the mechanical noises.
Have you asked the tuner to comment on knock retard vs. spark advance vs. RPM/MAP?
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